The invention provides a short term load forecasting-based on-load capacity regulating method for a distribution transformer; the distribution transformer is a self-adaption load-type distribution transformer or an on-load capacity regulating distribution transformer. The method comprises the following steps: performing real-time monitoring on a load condition and performing record keeping; performing short term load forecasting, and further generating a state level; determining the on-load capacity regulating strategy of the distribution transformer and performing related operations. According to the short term load forecasting-based on-load capacity regulating method for the distribution transformer, provided by the invention, on the basis of the self-adaption short term load forecasting, the short term load forecasting of a distribution room is considered during the on-load capacity regulating process of the distribution transformer, so that the on-load capacity regulating control of the distribution transformer is optimized, frequent capacity regulating caused by load fluctuation of the distribution room is reduced, the cost performance of a capacity regulating switch is improved, the service life of the capacity regulating switch is prolonged, and the shock to a distribution network is reduced.